I've always used sheets of newspaper, usually a couple thick, to line the bottom of my chicks' box. Never had any problems related to the newspaper itself. However, I've also been putting a layer of grass clippings in on top of the newspaper. Not so much for safety, though--more just because I think it makes a more natural, comfortable environment for the little buggers. It gives them something to scratch through and play around with and nestle down in (they even eat a little). I think anything like it, such as wood shavings, straw, leaves, whatever you have around, would work for that purpose. Once it gets funky inside the box, it's a simply chore to carefully roll up the newspaper, keeping all the grass and poop inside, and then bury the whole lot in the compost heap.
The newspaper itself is OK as a lining, I think, but you should definitely put something else on top of it so they can scratch and play around in a natural way.
Hope this is helpful,
Aloha,
Sky